1. Field of the Invention
The present invention relates to a monitor. More specifically, the present invention relates to a monitor having a self testing circuit.
2. Description of the Prior Art
Prior art monitor utilizes its OSD (On Screen Display) function and a micro-controller to achieve self testing of the monitor. When a user wants to know if the monitor is in a good operation, he can disconnect the monitor from a computer. If the monitor indicates a message, e.g. xe2x80x9cno signalxe2x80x9d on the panel successfully to show that no video signals from the computer are received, that means the monitor is not out of function.
When the monitor is disconnected from the computer, the micro-controller of the monitor is not able to receive video signals from the computer. Therefore, the micro-controller activates the OSD function of the monitor to indicate a message, e.g. xe2x80x9cno signalxe2x80x9d on the panel. If the message is successfully shown on the panel, it means the monitor is not out of function. Otherwise, it means the monitor is out of function.
However, not all monitors are accommodated with a micro-controller or OSD function. Such monitors are not capable of performing self testing function. That is, for those monitors that don""t possess micro-controller and OSD function, they are, in general, not able to perform self testing function.
It is therefore a primary objective of this invention to provide a monitor having a self testing circuit. Self testing function can be achieved even lack of OSD facility and micro-controller in such a monitor.
The monitor according to the present invention comprises a display panel, a displaying circuit, a connector and a self testing circuit. The self testing circuit is electrically connected to an input port of the displaying circuit. It comprises a testing signal, a switch circuit and a detecting circuit. When the detecting circuit detects video signals transmitted from the computer, the detecting circuit switches off the switch circuit so as to avoid the testing signal generated from the testing signal generator being transmitted to the input port of the displaying circuit. When the detecting circuit detects no video signals from the computer, the detecting circuit switches on the switch circuit so as to allow the testing signal generated from the testing signal generator to be transmitted to the displaying circuit.
It is an advantage of the present invention that the monitor can perform self-testing without using OSD or the microcontroller installed therein.
These and other objects and the advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.